US 330 was among the original 1926 routes. For its first seven years, its east end was in downtown Chicago. During that time, its east terminus was first in Geneva, and then in West Dundee (both endpoints are discussed in detail on the Fox River Valley page).

​In about 1933, Roosevelt was extended further east through Chicago, so the US 330 designation was extended along with it, and then quite a ways to the south, where it ended at US 30 in what is now Lynwood. A detailed map shows that, initially, US 330 used a small segment of Glenwood-Dyer Road between US 30 and Torrence Avenue:

c. 1934

This photo was looking north on westbound US 30/Lincoln Hwy, which continues to the left. IL hwy. 83 begins straight ahead on Glenwood-Dyer, and that was the former beginning of US 330. Glenwood-Dyer curves to the northwest and meets Torrence after about a mile:

Hargraves, June 2002

This shot was taken from the opposite direction. IL 83 ends here, as did historic US 330 (straight ahead is eastbound US 30)...

Hargraves, June 2002

...but that lasted for only a few years. In about 1937, US 330 traffic was redirected to simply stay on Torrence for the remaining distance down to US 30. This image was looking south on Torrence, in what is now Sauk Village. Until its decommissioning in 1942, US 330 ended at the traffic signal ahead, at its junction with US 30:

Google Maps Street View, Oct. 2013

Around 1937 was also the time when US 30 to the west of Chicagoland began to resemble its current route. Instead of going north all the way to Geneva before turning west, US 30 was changed to head west from Aurora (as it does today). So the US 330 designation was removed from the segment between Geneva and West Dundee, and instead extended west from Geneva along the former route of US 30 (which is IL 38 today). At first the "new" US 30 was complete only as far west as Amboy; from there it went northwest with US 52 to Dixon, where it connected with its original alignment. So the west end of US 330 was at its junction with US 30 in Dixon:

c. 1939, IL DoT

US 330 came into Dixon on today's IL 38, ending at US 52 (which carried US 30 traffic for a few years):

Sanderson, Aug. 2005

Morrison, Aug. 2016

Downtown is a few blocks ahead. Here is a shot from the opposite direction: this was eastbound US 30, which continued to the right. The west beginning of US 330 was straight ahead:

Sanderson, Aug. 2005

Next is a photo from the perspective of historic westbound US 30, which continued to the left, while US 330 began to the right:

Sanderson, Aug. 2005

By about 1941, US 30 was extended further west along its current path, which goes through Rock Falls, bypassing Dixon and Sterling. So then the US 330 designation was extended west along former US 30 through Dixon and Sterling, ending just west of Sterling near Galt. This photo was looking east on US 30:

Sanderson, Aug. 2005

Until recently, a left turn there put drivers on the west beginning of IL hwy. 2. But in the early 1940s, that was the west beginning of US 330. However, that lasted only a year or two, until the US 330 designation was decommissioned, and instead re-signed as Alternate US 30.